Frost Found On Asteroid

Any school kid can tell you that comets are made of ice. That frozen water burning off is what gives comets their characteristic tails. But asteroids were generally thought to be dry. Or at least frost-free. Now two studies published in the journal Nature [Andrew Rivkin and Joshua Emery, http://bit.ly/bkL3DU and Humberto Campins et al, http://bit.ly/bI8Eqa ] suggest that notion may be all wet. Because at least one asteroid appears to be coated by a thin layer of ice. And just that kind of asteroidal frosting could have been the source of our water here on Earth. [More]